# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
    def findKthToTail(self, pListHead, k):
        """
        :type pListHead: ListNode
        :type k: int
        :rtype: ListNode
        """
        if pListHead == None:
            return None
        arr = []
        b = pListHead
        while(True):
            if b.next != None:
                arr.append(b.val)
                b = b.next
            else:
                arr.append(b.val)
                break
        
        if k > len(arr):
            return None
        
        cnt = 0
        b = pListHead
        while(True):
            if cnt == len(arr) - k:
                return b
            else :
                b = b.next
                cnt += 1